Leukoerythroblastosis can be defined as the presence of both immature WBCs (metamyelocytes or earlier cells) and nucleated RBCs in the peripheral blood smear. Although the relative frequency of etiologies is different in different reports, approximately 25%-30% of patients with leukoerythroblastosis have metastatic tumor in the bone marrow, about 20% have leukemia, about 10% have myeloid metaplasia or polycythemia vera, and about 8% have hemolytic anemia. Severe infection, megaloblastic anemia, and severe acute hemorrhage account for about 5% each. There is a miscellaneous nonneoplastic group with relatively few cases of any single etiology comprising 5%-15% of the total.
Tag: White Blood Cells
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Neutropenia (Granulocytopenia)
Neutropenia is usually defined as a WBC count less than 4,000/mm3. Some conditions associated with neutropenia include (1) conditions associated with pancytopenia, such as megaloblastic anemia, aplastic anemia, acute or aleukemic leukemia, hypersplenism of varying etiology (e.g., cirrhosis, systemic lupus, Gaucher’s disease), and paroxysmal nocturnal hemoglobinuria, (2) drug-induced neutropenia (agranulocytosis), (3) certain infections, such as typhoid, some viral infections (e.g., Epstein-Barr, in the first week of illness, and the hepatitis viruses), overwhelming bacterial infection (septicemia, miliary tuberculosis), and (4) cyclic and chronic idiopathic neutropenia. In one study, neutropenia was present in 3% of inpatient children and 7% of outpatient children. In another study, the median duration of isolated neutropenia in children was 7-14 days, with total duration of 30 days in 70% of patients. In two studies, the risk of developing an infection in a febrile neutropenic child who otherwise appears well was about 3%-5%.
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Lymphocytosis
Lymphocytosis is most commonly associated with a normal or a decreased total WBC count. The most common etiology is viral infection. The lymphocytosis seen in the majority of viral infections is actually a relative type due to a decrease in granulocytes while total (absolute) lymphocyte numbers remain constant. The same phenomenon is found in Addison’s disease and in drug-induced agranulocytosis. A real (absolute) lymphocytosis with leukocytosis occurs in pertussis, infectious lymphocytosis, lymphocytic leukemia, and in some infants with adenovirus infection. Infectious mononucleosis, adult cytomegalovirus infection, and sometimes hepatitis virus infection are associated with absolute lymphocytosis and atypical lymphocytes; there may be leukopenia in the early stages, which is followed by leukocytosis. Toxoplasmosis sometimes produces absolute lymphocytosis. One report indicates that severe trauma may be associated with absolute lymphocytosis that changes to lymphopenia accompanied by increased granulocytes within 24 hours.
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Leukemoid Reaction
Leukemoid reaction is usually defined as a nonleukemic WBC count more than 50,000/mm3 (50 х 109/L) or a differential count with more than 5% metamyelocytes or earlier cells. It is basically a more severe or pronounced form of ordinary nonneoplastic granulocyte reaction. Some conditions associated with leukemoid reaction are severe bacterial infections, severe toxic states (burns, tissue necrosis, etc.), extensive bone marrow replacement by tumor, severe hemolytic anemia, severe acute blood loss, and juvenile rheumatoid arthritis.
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White Blood Cells
White blood cells (WBCs, leukocytes) form the first line of defense of the body against invading microorganisms. Neutrophils and monocytes respond by phagocytosis; lymphocytes and plasma cells primarily produce antibodies. In addition to a nonspecific response to bacterial or viral infection, there are alterations in the normal leukocyte blood picture that may provide diagnostic clues to specific diseases, both benign and malignant. Nonneoplastic leukocyte alterations may be quantitative, qualitative, or both; qualitatively, leukocytes may demonstrate an increased degree of immaturity, morphologic alteration in cellular structure, or the increased production of less common types of WBCs.